INTRACAVITARY ULTRASOUND PROBE

1 - 7 . (canceled)

8 . An intracavitary ultrasound probe, comprising:

a housing comprising:

an insertion section having a center axis; and

a holding section extending in a longitudinal direction of the housing, the holding section being connected to one end of the insertion section so that the center axis and the longitudinal direction are parallel to each other; and

an ultrasound unit built into the insertion section at a position on another end of the insertion section,

wherein the holding section has:

a first axis that matches with the center axis of the insertion section; and

a second axis that passes through a center of a first cross section perpendicular to the longitudinal direction of the holding section, and extends in parallel to the longitudinal direction,

wherein the holding section comprises:

a first holding section through which the first axis passes; and

a second holding section connected to the first holding section,

wherein, in a second cross section perpendicular to the longitudinal direction of the holding on the first axis is offset from the second axis in a first direction,

wherein, in the second cross section, an outer surface of the first holding section comprises a first curved portion having a first curvature,

wherein, in the second cross section, an outer surface of the second holding section comprises a second curved portion having a second curvature, and

wherein the first curvature is smaller than the second curvature.

9 . The intracavitary ultrasound probe according to claim 8 ,

wherein, in the second cross section, the first curved portion comprises a substantial arc, and

wherein a center of the substantial arc is located in the vicinity of the first axis in the second cross section.

10 . The intracavitary ultrasound probe according to claim 9 ,

wherein the housing comprises a first bulging portion disposed at a position closer to the insertion section from a longitudinal center of the holding section in the longitudinal direction, and

wherein a width of the first bulging portion in the first direction in a third cross section perpendicular to the longitudinal direction of the first bulging portion is larger than a width of the holding section in the first direction in a fourth cross section perpendicular to the longitudinal direction and taken in the longitudinal center of the holding section.

11 . The intracavitary ultrasound probe according to claim 10 ,

wherein the housing comprises a second bulging portion disposed at a position closer to, from the longitudinal center of the holding section, an end of the housing opposite to an end of the holding section connected to the insertion section,

and

wherein a width of the second bulging portion in the first direction in a fifth cross section perpendicular to the longitudinal direction of the second bulging portion is larger than the width of the holding section in the first direction in the fourth cross section.

12 . The intracavitary ultrasound probe according to claim 11 ,

wherein the width of the first bulging portion in the first direction in the third cross section is larger than the width of the second bulging portion in the first direction in the fifth cross section.

13 . The intracavitary ultrasound probe according to claim 8 ,

wherein in the second cross section, the outer surface of the first holding section comprises a substantially straight line portion.

14 . The intracavitary ultrasound probe according to claim 8 ,

wherein an outer surface of the holding section in the second cross section has a substantially symmetrical shape with respect to a plane including the first axis and the second axis.

15 . The intracavitary ultrasound probe according to claim 8 ,

wherein, in the second cross section, the first curved portion is located on a line extending from the second axis in the first direction.

16 . The intracavitary ultrasound probe according to claim 8 ,

wherein, in the second cross section, the second curved portion is located on a line extending from the second axis in a second direction opposite to the first direction.

17 . The intracavitary ultrasound probe according to claim 8 ,

wherein, in the second cross section, a curvature of the outer surface of the second holding section increases from a portion connecting the first holding section and the second holding section.

18 . The intracavitary ultrasound probe according to claim 8 ,

wherein, in the second cross section, all of curvatures of an outer surface of the holding section, when viewed from the second axis, have zero or positive values.

19 . The intracavitary ultrasound probe according to claim 8 ,

wherein, in the second cross section, the first curved portion comprises a substantial arc, and

wherein a center of the substantial arc is located between the first axis and the second axis and closer to the first axis than to the second axis, in the second cross section.